This invention relates to a data carrier, in particular a smart card, with a battery and a display.
For payment transactions there has been introduced in recent years a money card, a so-called electronic purse, which is formed by a smart card. At suitably designed terminals one can load amounts of money into the electronic memory of the smart card to be used later for the payment of purchases.
Known smart cards have the disadvantage, however, that the user cannot see which amount of money is still available. The article “Dünn wie Papier,” Wirtschaftswoche, 21 Jan. 1999, discloses a smart card that permits a user to find out the particular amount of money available. The smart card has for this purpose a display that is supplied by a flat battery and can be activated by means of a switch.
Because of the small volume of the smart card, it must be guaranteed for a long life that the display is only supplied with power when this is intended by the user of the smart card. This cannot be reliably guaranteed in the known smart card since smart cards are usually kept in wallets or billfolds. The probability of inadvertent operation of the switch is therefore very high since in the wallet or billfold the smart card is constantly subjected to pressure from both sides which can also act on the switch. This would lead to relatively rapid discharge of the battery, thereby reducing the life of the smart card altogether.
It is therefore the problem of the present invention to state a data carrier, in particular a smart card, in which no inadvertent discharge of the battery can occur.